The present invention is in the field of enzyme proteins that are related to the synthase enzyme subfamily, recombinant DNA molecules, and protein production. The present invention specifically provides novel peptides and proteins and nucleic acid molecules encoding such peptide and protein molecules, all of which are useful in the development of human therapeutics and diagnostic compositions and methods.
Many human enzymes serve as targets for the action of pharmaceutically active compounds. Several classes of human enzymes that serve as such targets include helicase, steroid esterase and sulfatase, convertase, synthase, dehydrogenase, monoxygenase, transferase, kinase, glutanase, decarboxylase, isomerase and reductase. It is therefore important in developing new pharmaceutical compounds to identify target enzyme proteins that can be put into high-throughput screening formats. The present invention advances the state of the art by providing novel human drug target enzymes related to the synthase subfamily.
The novel human protein, and encoding gene, provided by the present invention is related to the family of synthase enzymes in general, and shows the greatest degree of similarity to human cytoplasmic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase. Furthermore, the protein of the present invention may be an alternative splice form of the HMG-CoA synthase enzyme provided in Genbank gi4504429 (see the amino acid sequence alignment in FIG. 2). HMG-CoA synthase, along with HMG-CoA reductase which is also found on human chromosome 5, is a transcriptionally regulated enzyme that is important in cholesterologenesis.
Mutation of Cys129 to serine or alanine has been shown to abolish HMG-CoA synthase activity by interrupting the first catalytic step, enzyme acetylation by acetyl coenzyme A, in HMG-COA synthesis (Rokosz et al., Arch. Biochem. Biophys. 312 (1), 1-13 (1994)). A beta-lactone inhibitor compound known as L-659,699, is a strong inhibitor of HMG-CoA synthase (Rokosz et al., Arch. Biochem. Biophys. 312 (1), 1-13 (1994)).
For a further review of HMG-CoA synthase, see Mehrabian et al., J. Biol Chem 1986 December 5;261(34):16249-55; Ayte et al., Proc. Nat. Acad. Sci. 87: 3874-3878, 1990; Gil et al., Proc. Nat. Acad. Sci. 84: 1863-1866, 1987; Leonard et al., Proc. Nat. Acad. Sci. 83: 2187-2189, 1986; and Russ et al., Biochim. Biophys. Acta 1132: 329-331, 1992.
Due to their importance in cholesterologenesis, novel human HMG-CoA synthase proteins/genes, such as provided by the present invention, are valuable as potential targets for the development of therapeutics to treat cholesterol-related diseases/disorders. Furthermore, SNPs in HMG-CoA synthase genes, such as provided by the present invention, are valuable markers for the diagnosis, prognosis, prevention, and/or treatment of cholesterol-related diseases/disorders.
Using the information provided by the present invention, reagents such as probes/primers for detecting the SNPs or the expression of the protein/gene provided herein may be readily developed and, if desired, incorporated into kit formats such as nucleic acid arrays, primer extension reactions coupled with mass spec detection (for SNP detection), or TaqMan PCR assays (Applied Biosystems, Foster City, Calif.).
Enzyme proteins, particularly members of the synthase enzyme subfamily, are a major target for drug action and development. Accordingly, it is valuable to the field of pharmaceutical development to identify and characterize previously unknown members of this subfamily of enzyme proteins. The present invention advances the state of the art by providing previously unidentified human enzyme proteins, and the polynucleotides encoding them, that have homology to members of the synthase enzyme subfamily. These novel compositions are useful in the diagnosis, prevention and treatment of biological processes associated with human diseases.
The present invention is based in part on the identification of amino acid sequences of human enzyme peptides and proteins that are related to the synthase enzyme subfamily, as well as allelic variants and other mammalian orthologs thereof. These unique peptide sequences, and nucleic acid sequences that encode these peptides, can be used as models for the development of human therapeutic targets, aid in the identification of therapeutic proteins, and serve as targets for the development of human therapeutic agents that modulate enzyme activity in cells and tissues that express the enzyme. Experimental data as provided in FIG. 1 indicates expression in humans in teratocarcinoma and teratocarcinoma neuronal precursor cells, fetal brain, liver and liver adenocarcinoma, lung small cell carinoma, and the genitourinary tract.